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Feline Infectious Peritonitis
❯❯ T eresa L. Goodson, DVM,
DACVIM (Small Animal
Medicine)
❯❯ S
usan C. Randell, BVSc,
DACVIM (Small Animal
Medicine)
❯❯ L isa E. Moore, DVM,
DACVIM (Small Animal
Medicine)
Affiliated Veterinary Specialists
Maitland, Florida
At a Glance
Causative Agents
Page E1
Pathogenesis
Page E1
Signalment
Page E2
Clinical Signs
Page E2
Diagnostic Tests
Page E3
Treatment
Page E5
Prognosis
Page E6
Prevention
Page E6
Abstract: Feline infectious peritonitis (FIP) frequently results in death in cats. It is caused by a
mutated, highly contagious coronavirus, and it is more common in indoor cats in multicat households. A complex interaction between the coronavirus and the feline immune system causes
disseminated vasculitis, which is the hallmark of FIP. New tests are being developed, but the antemortem diagnosis of FIP continues to be difficult and frustrating. Current treatments are crude
and involve supportive care and immunosuppression. Minimizing exposure is the best method
of preventing infection.
F
eline infectious peritonitis (FIP) is
caused by a mutated coronavirus
and frequently results in death in
cats. The difficulty of establishing the
diagnosis and the lack of effective treatment options have frustrated veterinarians since FIP was identified more than
40 years ago.1 Research is clarifying
the complex pathogenesis of FIP. This
review addresses the pathogenesis and
clinical signs of FIP, as well as the current diagnostic tests and management
recommendations.
Causative Agents
Feline coronavirus is a large, enveloped
RNA virus that exists in two forms: feline
enteric coronavirus (FECV) and feline
infectious peritonitis virus (FIPV). FECV
is virtually nonpathogenic, whereas FIPV
is almost invariably fatal.1 All FECV carriers have the potential to develop either
enteritis or peritonitis, although only
about 5% of infections develop into FIP.1
Currently available diagnostic tests cannot
differentiate FECV from FIPV with 100%
accuracy.
Multicat households have a much
higher prevalence of FECV (75% to 100%)
than single-cat households (25%).2–4
Animal shelters and catteries facilitate the
transmission of FECV because of high
environmental stress and sharing of contaminated litterboxes.4,5 Increases of up to
a millionfold in fecal shedding of FECV
were seen in FECV-positive cats after
entering an animal shelter.6 Half of the
cats that were originally FECV negative
were shedding FECV within 1 week of
entering the shelter.6
Pathogenesis
FECV, which is highly contagious, is
transmitted primarily via the fecal–oral
route, although it may also be transmitted
by inhalation.1 It replicates in the epithelial cells of the intestinal tract. Fecal shedding begins within 2 days of infection,
and seroconversion occurs within 18 to 21
days after exposure to the virus.1 FECV
replicates only in enterocytes. It can exist
in the systemic circulation but cannot sustain viral production there, so progression
to FIP does not occur.7 However, if a crucial deletion mutation (typically of the 3C
or 7B gene) occurs, the virus can be taken
up by macrophages and gain access to the
systemic circulation, where it transforms
into the highly pathogenic FIPV.8 FIPV
infection is sustained in monocytes and
macrophages, where the virus undergoes
replication and spreads systemically.7
Traditionally, FIP has been divided into
two distinct clinical forms: effusive (wet)
and noneffusive (dry). Approximately three
times as many cats present with the wet
form as with the dry form.9 However,
these divisions are not absolute, as a combination of both forms is often present in
cats with FIP.10 The macrophage is the key
inflammatory cell in both forms of FIP.11
Cats that are infected with FECV but do
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Box 1
Breed Prevalence of FIP
21
Increased risk
Abyssinian
Bengal
Birman
Himalayan
Ragdoll
Rex
QuickNotes
FIP occurs primarily in indoor cats
housed in large
groups.
E2
No increased risk
Burmese
Exotic shorthair
Manx
Persian
Russian blue
Siamese
TNF-α, IL-6, and IL-12 appear to be associated with disease progression.15,17–19 The role
of all of these cytokines in the development
of humoral (Th2) and cell-mediated (Th1)
immune responses may be instrumental in
understanding the pathogenesis of FIP.15,19
Signalment
All felids are susceptible to FIP. Among nondomestic cats, cheetahs are particularly vulnerable.20 Among domestic cats, young cats aged
3 months to 3 years and geriatric cats older
not develop FIP are believed to mount a strong than 13 years are most frequently affected.9,12
cell-mediated response, although other, unde- Sexually intact cats, males, and purebred
termined factors are likely involved.1,12 A lack cats have a higher incidence of FIP.9,21,22
of cell-mediated immunity, combined with a Susceptibility to FIP is a polygenic inherited
strong humoral response by the host, leads trait in Persians and Birmans.23 However, a
to the effusive form of FIP.12 Host antibodies recent study revealed differences between
and viral antigens form immune complexes breeds in the prevalence of FIP21 (Box 1).
that are deposited on the vascular endothelium, causing vasculitis with resultant leakage Clinical Signs
of proteinaceous fluid. Adhesion of infected FECV infection may manifest as a benign
monocytes to the endothelium activates com- illness limited to mild diarrhea that rarely
plement, causing the release of vasoactive requires veterinary attention.1 Some cats show
amines that retract the vascular endothelium, no clinical signs of infection.
allowing further protein and fluid exudation.1 Cats with wet FIP are typically ill and
When virus-infected monocytes enter tissue, debilitated.1,10 Fever or uveitis may be presthey attract antibodies that fix complement, ent.1,10 These cats exhibit abdominal distendrawing in more macrophages and neutrophils tion, pallor, tachypnea, dyspnea, or muffled
and creating a perivascular pyogranulomatous heart sounds as a result of fluid accumulation
in the peritoneal or pleural cavities1 (Figure 1).
inflammation.1
Experimentally infected monocytes and Pericardial effusion is less common.1 Effusion
macrophages do not express surface viral pro- into body cavities is a nonspecific finding
teins; rather, viral proteins are rapidly inter- without cytologic evaluation of the fluid; siminalized following exposure to FIPV-specific lar effusions occur in a variety of diseases
antibodies. This allows the virus to evade (e.g., lymphoma, hepatic neoplasia, cholangantibody-dependent lysis, so the humoral iohepatitis, congestive heart failure, bacterial
response fails to clear FIPV infection.13,14
peritonitis/pleuritis).
If a partial cell-mediated response is mounted, Clinical signs of the dry form can be vague
the noneffusive form of FIP results, and large and nonspecific, including lethargy, poor
pyogranulomas form in many organs.12 The appetite, weight loss, icterus, and an intermitvasculitis present in dry FIP is not severe tent fever that does not respond to antibiotics.1
enough to cause the effusion that occurs in Kittens may have stunted growth and diarrhea.
Ocular lesions include iritis, uveitis, and cuffwet FIP.1
The patterns of expression of various ing of the retinal vasculature1,24 (Figure 2). Cats
cytokines in the peripheral blood monocytes, with neurologic involvement frequently exhibit
macrophages, lymphoid tissue, and ascitic ataxia, nystagmus, and seizures.25 Abdominal
fluid of cats with FIP are being studied exten- palpation may reveal enlarged lymph nodes
sively. Tumor necrosis factor (TNF)-α, inter- and irregular organ surfaces, especially the
feron (INF)-γ, interleukin (IL)-6, IL-10, and kidneys. Less commonly reported clinical signs
IL-12 appear to play roles in the develop- include intestinal granuloma (often colonic),
ment of FIP.11,15–19 Increases in INF-γ and IL-10 massively enlarged abdominal lymph nodes,
may be protective,11,15,18 whereas increases in orchitis, skin lesions, and pneumonia.1,26–30
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Diagnostic Tests
FIGURE 1
No single sensitive, specific, noninvasive diag­
nostic test for FIP is currently available.
Therefore, test results must be combined with
the history and clinical signs to establish the
diagnosis.
The complete blood cell count (CBC) often
reveals lymphopenia, neutrophilia, nonregen­
erative anemia, and thrombocytopenia. Lympho­
penia is due to virus-induced apoptosis of
lymphoid tissue.31,32 Neutrophilia characterizes
a stress leukogram secondary to infection.10
Nonregenerative anemia is due to chronic
inflammation.10 Thrombocytopenia may be due
to immune-mediated destruction or decreased
bone marrow production of platelets.33
Cat with FIP showing emaciation and abdominal fluid distention.
Hyperglobulinemia is observed in more
than 70% of patients with FIP. Elevated serum
FIGURE 2
globulin levels may be due to the antibodies
produced during the host’s humoral immune
response to the virus, as well as the presence
of complement and immune complexes.34,35
Mild hypoalbuminemia may be due to de­creased albumin production by the liver or
increased loss from endothelial leakage. The
serum albumin:globulin ratio (A:G) should
be calculated: a value of <0.8 indicates that
the cat likely has FIP (92% positive predictive value [PPV]), whereas a serum A:G >0.8
makes FIP unlikely (61% negative predictive
value [NPV]).10 An elevated bilirubin level is
likely due to liver necrosis. Liver enzyme levels are frequently normal.1 Additional serum
biochemical abnormalities reflect the organs Anterior uveitis due to FIP.
affected by vasculitis and subsequent lack
of blood supply. Disseminated intravascular
coagulopathy and coagulopathies caused by unclear, but the protein may prove to be a
liver necrosis and increased platelet reactivity useful biomarker.37,38 Serum amyloid A (SAA),
another acute-phase protein, increases 10-fold
can also be seen.36
Serum protein electrophoresis may reveal a in the serum of cats with FIP compared with
polyclonal or a monoclonal gammopathy, so healthy cats exposed to FECV.1,38 SAA may also
this test does not help distinguish FIP from other be useful as a biomarker in the future. At this
time, no validated commercial test is available
diseases that cause hyperglobulinemia.10
Alpha-1-acid glycoprotein (AGP) is an acute- for routine evaluation of AGP and SAA levels.
phase protein, the serum level of which is
elevated in many infectious and inflammatory Analysis of Effusion Fluid
diseases. AGP controls lymphocyte produc- FIP effusion fluid is typically a straw-colored,
tion of cytokines by modulating neutrophil modified transudate that contains a high level
and lymphocyte responses. Levels of AGP in of protein (>3.5 g/dL) and few cells (<5000
serum and effusions increase twofold to five- nucleated cells/mL; Figure 3).1 The fluid may
fold in cats with FIP, more than in diseases also be classified as an exudate or, rarely, as
such as neoplasia and cardiomyopathy. The chyle.39 The high protein content comes from
role of AGP in the development of FIP is leakage of globulins across the damaged
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FIGURE 3
Abdominal effusion fluid removed from a cat with FIP.
QuickNotes
No single sensitive,
specific, noninvasive diag­nostic test
for FIP is currently
available.
vascular endothelium. Neutrophils and macrophages in the fluid are consistent with pyogranulomatous inflammation.
The A:G ratio of the effusion should be measured: a ratio of <0.5 is strongly correlated with
FIP, with a PPV between 66% and 95%, depending on the prevalence of FIP in the cat’s environment.3 An A:G ratio >0.81 has a 100% NPV,
essentially ruling out FIP.1,3,12,40 In some cases,
the results of the CBC, serum chemistry, fluid
analysis, and cytology—combined with a thorough history and physical findings—may be
sufficient for a presumptive diagnosis of FIP.
Rivalta’s test can be performed to exclude
FIP as a cause of effusion.3,10 This test has
an 86% PPV and a 97% NPV for FIP.10 One
drop of 98% acetic acid (not vinegar) is mixed
into a test tube containing 5 mL of distilled
water.3,10 One drop of effusion fluid is gently
added to the mixture. If the drop dissolves
and disappears, the result is negative, so FIP
can be ruled out as the cause of effusion. If
the drop holds its shape due to high levels
of protein, fibrin, and inflammatory mediators,
the result is positive.41 Diseases other than FIP
that produce positive results on Rivalta’s test
are lymphoma and bacterial peritonitis, which
can usually be distinguished by cytologic
evaluation of the fluid.10 Rivalta’s test is not
frequently used because 98% acetic acid is not
readily available in most veterinary practices.
a very low PPV for FIP (44%).3 However, a
very high titer (1:1600) has a 94% PPV for FIP.3
A negative titer has a 90% NPV for FIP.3 The
magnitude of the coronavirus titer may be
helpful when evaluated in conjunction with
clinical signs and other test results.3
Viral titers do not always correlate with
fecal shedding of FECV.43 A commercial test
for the 7B antibody is available, and it initially
showed promise in differentiating FIPV from
FECV. However, additional studies showed the
7B antibody test to have false positives in some
healthy cats with FECV infection. Because this
test cannot reliably differentiate between FIPV
and FECV, it has little diagnostic usefulness.44
Testing for anticoronavirus antibodies in
effusion fluid may be more useful than testing
serum. Detection of anticoronavirus antibodies
in effusion fluid has a PPV of 90% and an NPV
of 79% for the diagnosis of FIP.3 Laboratories
vary widely with regard to reporting anticoronavirus antibody titer results, making interpretation very difficult.10 Antibody titers should
be interpreted carefully and should never be
used as the sole test to diagnose FIP.
The diagnostic value of anticoronavirus
titers in cerebrospinal fluid (CSF) for the diagnosis of FIP involving the central nervous
system (CNS) is questionable. A recent study45
demonstrated anticoronavirus antibodies in
the CSF of cats with neurologic FIP, cats with
FIP not involving the CSF, and cats with brain
tumors. The cats with positive titers in the CSF
also had high serum titers. This finding is consistent with blood contamination of the CSF
sample. Detection of anticoronavirus antibodies in the CSF offers no diagnostic advantage
over serum titers, which are of limited value.
Polymerase Chain Reaction
Reverse transcription polymerase chain reaction (RT-PCR) can identify feline coronavirus
in effusion fluid, feces, tissue, or blood.10,42,43,46
Serology
Messenger RNA (mRNA) is only present when
Many commercial assays are available to detect the virus is replicating, which is important
anticoronavirus antibodies in serum. However, in differentiating between FIPV and FECV.46
none can distinguish among FECV, other non- Although FECV can be present in the circulavirulent coronaviruses, and FIPV. Healthy cats tion, it does not replicate within monocytes, so
exposed to nonvirulent coronaviruses (e.g., no mRNA should be identified.46 When FIPV is
canine coronavirus, transmissible gastroen- circulating and replicating within monocytes
teritis virus) will be seropositive. Conversely, and tissue macrophages, it produces mRNA,
cats with fulminant, effusive FIP can be falsely which can be identified using RT-PCR.46 Be­seronegative.1,42 A positive titer (all levels) has cause it can be difficult to work with mRNA,
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a DNA copy (cDNA) is created in RT-PCR by
reverse-transcribing the mRNA. The cDNA is
then amplified using primers specific for the
highly conserved M gene so that large quantities of cDNA are available for identification of
the virus.46 Of cats with confirmed FIP, 93%
tested positive with RT-PCR, and no false positives occurred in the study group.46
However, RT-PCR results may be incorrect.
False negatives can occur because of degradation by RNases, ubiquitous enzymes that
can easily contaminate a sample. Laboratory
contamination and cross-reaction with other
coronaviruses (e.g., canine coronavirus, transmissible gastroenteritis virus) can produce
false-positive results.1
Auburn University’s College of Veterinary
Medicine Molecular Diagnostics Laboratory
is the only laboratory to offer the FIP mRNA
Multi Test. Samples of whole blood, effusion
fluid, and tissue/aspirate of an affected organ
are submitted for RT-PCR testing. The PPV and
NPV of this combined test are both reportedly
close to 100%.47,a
Cerebrospinal Fluid Analysis and Central
Nervous System Imaging
Neurologic abnormalities are present in approximately 35% of cats with FIP.25,48 CSF
analysis may reveal an elevated protein content or pleocytosis (lymphocytes and neutrophils).10,49,50 FIP should be strongly suspected
in a cat with inflammatory CNS disease and
hydrocephalus identified on magnetic resonance imaging or computed tomography.25,48,51
Histopathology
Histopathology is the gold standard for the
diagnosis of FIP.3,12 Without histopathology,
any diagnosis of FIP is considered presumptive. However, cats with FIP are extremely
debilitated, making exploratory surgery for
biopsies risky and impractical. Fine-needle
aspiration and Tru-Cut biopsy of the liver
and kidneys have been evaluated as diagnostic tests for FIP. Lesions consistent with FIP
can be identified using these techniques, and
combining fine-needle aspiration and Tru-Cut
biopsy of the liver has the highest sensitivaMore
information about this test, including pricing and shipping methods, may be obtained at the
Auburn University College of Veterinary Medicine
Web site (www.vetmed.auburn.edu).
ity (86%). However, false negatives and inadequate samples are common, yielding a very
low diagnostic sensitivity (11% to 38%).52
In many cases, lesions are observed only
at necropsy. The classic lesions are pyogranulomatous inflammation that has caused vasculitis, necrosis, and fibrosis.12 The wet form of
FIP affects a large number of blood vessels,
causing the typical effusion, and small plaques
form on the surfaces of abdominal and thoracic
organs. In the dry form, larger pyogranulomas
affect the kidneys, liver, eyes, and CNS.19,50
Solitary mural FIP lesions of the colon or ileocecocolic junction may be grossly mistaken
for neoplasia.26 Meningitis, ependymitis, and
hydrocephalus are seen in the neurologic form
of FIP.25,50 Lymphoid depletion is commonly
observed in the spleen and lymph nodes of
cats that succumb to FIP.32 Lymphoid tissue is
hyperplastic in cats that survive infection.32
Immunofluorescent staining identifies the
coronavirus within macrophages in effusion
fluid or tissue. This test is 100% specific but
only 50% sensitive for FIP when performed
on effusion samples.3,10 In other words, FECV
should not be found in macrophages in effusion samples, so a positive result indicates that
the cat has FIP. Low numbers of macrophages
with insufficient virus to create fluorescence
can lead to a false-negative result.10 RT-PCR
can also be performed on tissue that has not
been preserved in formalin.47
QuickNotes
The macrophage
is the key inflammatory cell in the
development of FIP.
Treatment
No curative treatment exists for FIP. Therapy
is directed at suppressing the formation of
immune complexes and thus trying to control
the vasculitis that characterizes the disease.
Supplemental therapies to increase the overall well-being of the cat, including fluids and
nutritional support, should be provided.
If an owner or breeder chooses to test
healthy cats, cats identified as FECV seropositive should not be subjected to stress because
the onset of clinical signs is frequently seen
after events such as elective surgery or introduction to a new home.1 Avoiding stress in
group-housing situations is especially important. Cats with diarrhea suspected to be due
to FECV should be managed with supportive
care to maintain hydration, weight, and intestinal bacterial balance.1
Because the immune system of cats with FIP
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QuickNotes
Reverse transcription polymerase
chain reaction is a
promising test for
the accurate diagnosis of FIP.
E6
is impaired, immunosuppressive therapy may vector (e.g., litterboxes) when housing groups
be contraindicated.53 However, prednisone, of cats. One litterbox should be provided for
intracavitary dexamethasone, and cyclophos- each cat, and the litterboxes should be cleaned
phamide may be used to control the immune daily to reduce fecal contamination.59
response to the virus and temporarily improve Queens should be isolated from all other
the cat’s quality of life.1,10 Ribavirin is an antivi- cats 2 to 3 weeks before delivery. Strict isolaral agent with activity against FECV, but its use tion and sanitation should be continued until
is limited by its severe toxicity in cats, which the kittens are weaned at 5 weeks of age. The
causes hemolysis, bone marrow suppression, kittens should be maintained in isolation until
and liver damage.54
they are removed from the cattery. Infected
Various supplements have been used anec- queens can produce kittens negative for FECV
dotally with variable reports of success. High- if the kittens are strictly isolated and weaned
dose injectable human INF-α (104 to 10 6 IU/kg early.60 No cat that produces two or more kitSC q24h) inhibits viral nucleic acid and protein tens with FIP should be bred, since a genetic
synthesis. Cats develop neutralizing antibodies predisposition has been shown.21,23
to human INF-α within 3 to 7 weeks, limiting Any cat entering a cattery should be
its usefulness.55 Low-dose oral human INF-α (1 screened with FECV serology or fecal RT-PCR
to 50 IU/kg PO q24h) has immunomodulatory and isolated before introduction to the geneffects that may cause progression of FIP and eral cat population.43 Kittens can be screened
is not recommended.56 Feline INF-ω inhibits as young as 10 weeks of age.1 Cats with high
FECV in vitro and is available in some coun- titers, low titers, and negative titers should
tries. A recent report described a small num- be housed separately. As its titer decreases, a
ber of cats with suspected (not definitively cat can be housed with other nonshedders.2
diagnosed) FIP that were treated with gluco- Chronic shedders should be removed to elimicorticoids as well as feline INF-ω.57 No well- nate a source of FECV in the cattery. A cat, and
controlled studies have been performed to ultimately a cattery, may be considered FECV
assess the effectiveness of feline INF-ω against negative after 5 consecutive months of neganaturally occurring FIP. Propionibacterium acnes tive fecal RT-PCR tests and serology tests.43
is a nonspecific immunostimulant that may
enhance cell-mediated immunity, but no effi- Individual Households
An exposed, seropositive, ill cat should be
cacy against FIP has been documented.58
suspected of having FIP and should be approPrognosis
priately evaluated, isolated, and treated. A
Because there is no definitive treatment, the healthy cat that has been exposed to a cat that
prognosis for FIP is grave.59 Cats with the effu- succumbed to FIP should be carefully monisive form of FIP usually survive less than 2 tored for any clinical signs of illness. FECV can
months after presentation and sometimes for remain infectious in the environment for more
only days or weeks.1,12 The clinical signs are than 7 weeks.1 Therefore, an owner should
devastating and rapidly progressive, so eutha- wait at least 3 months before introducing
nasia is justified when the cat has a diminish- another cat into the house.10 ing quality of life.1 The average survival time
for cats with noneffusive FIP is unpredictable, Vaccination
with clinical signs waxing and waning for An intranasal, temperature-sensitive vaccine
that stimulates mucosal immunity against
weeks to months.1
FECV was released in 1991. In field trials, the
Prevention
vaccine appeared to be safe and effective
Catteries and Shelters
for cats that had not been exposed to FECV
Minimizing exposure is the mainstay of pre- before vaccination.61,62 The efficacy of the vacventing the spread of this highly contagious cine is questionable in cats already exposed to
disease. Cats should be housed in groups FECV because mucosal immunity cannot proof five or fewer, with no contact between tect against viral mutation.61,62 Unfortunately,
groups.10 Sanitation is extremely important, most at-risk kittens are already exposed to
and attention should be given to any potential FECV before the vaccine can be administered
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starting at 16 weeks of age. The American
Association of Feline Practitioners lists the FIP
vaccine as “not generally recommended.”63
Conclusion
FIP is a devastating disseminated vasculitis
in cats that results from a complex interaction between a mutated FECV and the feline
immune system. The virus is highly contagious, so the disease is more common in
multicat households and in purebred cats in
catteries. Researchers are continuing to elucidate the complex pathophysiology of the dis-
References
1. Addie DD, Jarrett O. Feline coronavirus infections. In: Green CE,
ed. Infectious Diseases of the Dog and Cat. 3rd ed. St. Louis: Saunders Elsevier; 2006:88-102.
2. Barr MC. FIV, FeLV, and FIPV. Interpretation and misinterpretation of serological test results. Semin Vet Med Surg (Small Anim)
1996;11(3):144-153.
3. Hartmann K, Binder C, Hirschberger J, et al. Comparison of different tests to diagnose FIP. J Vet Intern Med 2003;17:781-790.
4. Addie DD. Clustering of feline coronaviruses in multicat households. Vet J 2000;159:8-9.
5. Addie DD, Dennis JM, Toth S, et al. Long-term impact on a
closed household of pet cats of natural infection with feline coronavirus, feline leukemia virus, and feline immunodeficiency virus. Vet
Rec 2000;146:419-424.
6. Pedersen NC, Sato R, Foley JE, et al. Common virus infections
in cats, before and after being placed in shelters, with emphasis on
FECV. J Feline Med Surg 2004;6:83-88.
7. Dewerchin HL, Cornelissen E, Nauwynck HJ. Replication of
feline coronaviruses in peripheral blood monocytes. Arch Virol
2005;150:2483-2500.
8. Vennema H, Poland A, Foley J, et al. Feline infectious peritonitis
viruses arise by mutation from endemic feline enteric coronaviruses. Virology 1998;243:150-157.
9. Rohrbach BW, Legendre AM, Baldwin CA, et al. Epidemiology
of feline infectious peritonitis among cats examined at veterinary
medical teaching hospitals. JAVMA 2001;218(7):1111-1115.
10.Hartmann K. Feline infectious peritonitis. Vet Clin North Am
Small Anim Pract 2005;35:39-79.
11.Berg AL, Ekman K, Belak S, et al. Cellular composition and
interferon-γ expression of the local inflammatory response in FIP.
Vet Microbiol 2005;111:15-23.
12.McReynolds C, Macy D. Feline infectious peritonitis. Part I. Etiology and diagnosis. Compend Contin Educ Pract Vet 1987;19(9):
1007-1016.
13.Dewerchin HL, Cornelissen E, Nauwynck HJ. FIPV-infected
monocytes internalize viral membrane-bound proteins upon antibody addition. J Gen Virol 2006;87:1685-1690.
14.Cornelissen E, Dewerchin HL, Van Hamme E, et al. Absence of
surface expression of FIPV antigens on infected cells isolated from
cats with FIP. Vet Microbiol 2007;121:131-137.
15.Kiss I, Poland AM, Pedersen NC. Disease outcome and cytokine
responses in cats immunized with an avirulent FIPV and challengeexposed with virulent FIPV. J Feline Med Surg 2004;6:89-97.
16.Gelain ME, Meli M, Paltrinieri S. Whole blood cytokine profiles
in cats infected by FCoV and healthy non-FCoV infected SPF cats. J
Feline Med Surg 2006;8:389-399.
17.Takano T, Hohdatsu T, Hashida Y, et al. A “possible” involvement of TNFα in apoptosis induction in peripheral blood lymphocytes of cats with FIP. Vet Microbiol 2007;119:121-131.
18.Dean GA, Olivry T, Stanton C, et al. In vivo cytokine response to
experimental FIPV infection. Vet Microbiol 2003;97:1-12.
ease, which should eventually lead to more
effective methods of prevention and cure.
The recent development of RT-PCR testing
is providing encouraging results for possible
antemortem diagnosis of FIP, although the
laboratory providing this test has not published any information regarding its validation
methods. Current treatments are crude at best
and involve supportive care and, sometimes,
blanket suppression of the host’s humoral and
cell-mediated immune responses. Minimizing
exposure is the best method for prevention of
infection.
QuickNotes
Minimizing exposure is the best
method for prevention of infection.
19.Gunn-Moore DA, Caney SMA, Gruffydd-Jones TJ. Antibody and
cytokine responses in kittens during the development of FIP. Vet
Immunol Immunopathol 1998;65:221-242.
20.Munson L, Marker L, Dubovi E, et al. Serosurvey of viral infections
in free-ranging Namibian cheetahs. J Wildl Dis 2004;40(1):23-31.
21.Pesteanu-Somogyi LD, Radzai C, Pressler BM. Prevalence of
feline infectious peritonitis in specific cat breeds. J Feline Med Surg
2006;8:1-5.
22.Holst BS, Englund L, Palacios S, et al. Prevalence of antibodies
against feline coronavirus and Chlamydophila felis in Swedish cats.
J Feline Med Surg 2006;8:207-211.
23.Foley JE, Pedersen NC. The inheritance of susceptibility to
feline infectious peritonitis in purebred catteries. Feline Pract
1996;24(1):14-22.
24.Colitz CMH. Feline uveitis: diagnosis and treatment. Clin Tech
Small Anim Pract 2005;20(2):117-120.
25.Foley JE, Lapointe JM, Koblik P, et al. Diagnostic features of
clinical neurologic FIP. J Vet Intern Med 1998;12:415-423.
26.Harvey CJ, Lopez JW, Hendrick MJ. An uncommon intestinal
manifestation of FIP. JAVMA 1996;209(6):1117-1120.
27.Kipar A, Koehler K, Bellmann S, et al. FIP presenting as a tumour in the abdominal cavity. Vet Rec 1999;144:118-122.
28.Siguroardottir OG, Kolbjornsen O, Lutz H. Orchitis in a cat associated with coronavirus infection. J Comp Path 2001;124:219-222.
29.Cannon MJ, Silkstone MA, Kipar AM. Cutaneous lesions associated with coronavirus-induced vasculitis in a cat with FIP and concurrent FIV infection. J Feline Med Surg 2005;7:233-236.
30.Macdonald ES, Norris CR, Berghaus RB, et al. Clinicopathologic
and radiographic features and etiologic agents in cats with histologically confirmed infectious pneumonia. JAVMA 2003;223(8):11421150.
31.Kipar A, Bellmann S, Gunn-Moore DA, et al. Histopathological
alterations of lymphatic tissues in cats without FIP after long-term
exposure to FIP virus. Vet Microbiol 1999;69:131-137.
32.Kipar A, Kohler K, Leukert W, et al. A comparison of lymphatic
tissues from cats with spontaneous FIP, cats with FIPV infections
but no FIP, and cats with no infection. J Comp Pathol 2001;125:182191.
33.Kohn B, Linden T, Leibold W. Platelet-bound antibodies detected by a flow cytometric assay in cats with thrombocytopenia. J
Feline Med Surg 2006;8:254-260.
34.Paltrinieri S, Cammarata MP, Cammarata G, et al. Some aspects
of humoral and cellular immunity in naturally occurring FIP. Vet Immunol Immunopathol 1998;65:205-220.
35.Paltrinieri S, Grieco V, Comazzi S, et al. Laboratory profiles in
cats with different pathological and immunohistochemical findings
due to FIP. J Feline Med Surg 2001;3:149-159.
36.Peterson JL, Couto CG, Wellman ML. Hemostatic disorders in
cats: a retrospective study and review of the literature. J Vet Intern
Med 1995;9(5):298-303.
37.Bence LM, Addie DD, Eckersall PD. An immunoturbidimet-
CompendiumVet.com | October 2009 | Compendium: Continuing Education for Veterinarians®
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FREE
CE Feline Infectious Peritonitis
ric assay for rapid quantitative measurement of feline alpha-1acid glycoprotein in serum and peritoneal fluid. Vet Clin Pathol
2005;34(4):335-340.
38.Giordano A, Spagnolo V, Colombo A, et al. Changes in some
acute phase protein and immunoglobulin concentrations in cats affected by FIP or exposed to FCoV. Vet J 2004;167:38-44.
39.Savary KCM, Sellon RK, Law JM. Chylous abdominal effusion
in a cat with FIP. JAAHA 2001;37:35-40.
40.Shelly SM, Scarlett-Kranz J, Blue JT. Protein electrophoresis
on effusions from cats as a diagnostic test for FIP. JAAHA 1988;
24(5):495-500.
41.Sakai N, Iijima S, Shiba K. Reinvestigation of clinical value of
Rivalta reaction of puncture fluid. Rinsho Byori 2004;52:877-882.
42.Gunn-Moore DA, Gruffydd-Jones TJ, Harbour DA. Detection of
feline coronaviruses by culture and RT-PCR of blood samples from
healthy cats and cats with clinical FIP. Vet Microbiol 1998;62:193205.
43.Addie DD, Jarrett O. Use of a reverse-transcriptase polymerase
chain reaction for monitoring the shedding of FCoV by healthy cats.
Vet Rec 2001;148:649-653.
44.Bell ET, Malik R, Norris JM. The relationship between the FCoV
antibody titre and the age, breed, gender, and health status of Australian cats. Aust Vet J 2006;84(1):2-7.
45.Boettcher IC, Steinberg T, Matiasek K, et al. Use of anti-coronavirus antibody testing of the CSF for diagnosis of FIP involving the
CNS in cats. JAVMA 2007;230(2):199-205.
46.Simons FA, Vennema H, Rofina JE. A mRNA PCR for the diagnosis of feline infectious peritonitis. J Virol Methods 2005;124:111116.
47.Auburn University College of Veterinary Medicine Molecular
Diagnostics: New FIP messenger RNA triple test. Accessed August
2007 at www.vetmed.auburn.edu/index.pl/feline_infectious_
peritonitis_virus.
48.Foley JE, Rand C, Leutenegger C. Inflammation and changes in
cytokine levels in neurological FIP. J Feline Med Surg 2003;5:313322.
49.Singh M, Foster DJ, Child G, et al. Inflammatory cerebrospinal
fluid analysis in cats: clinical diagnosis and outcome. J Feline Med
Surg 2005;7:77-93.
50.Foley JE, Leutenegger C. A review of coronavirus infection in
the CNS of cats and mice. J Vet Intern Med 2001;15:438-444.
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51.Negrin A, Lamb CR, Capello R, et al. Results of magnetic resonance imaging in 14 cats with meningoencephalitis. J Feline Med
Surg 2006,doi:10.1016/j.jfms.2006.09.001.
52.Giordano A, Paltrinieri S, Bertazzolo W. Sensitivity of Tru-Cut
and fine-needle aspiration biopsies of liver and kidney for diagnosis
of FIP. Vet Clin Pathol 2005;34(4):368-374.
53.Knotek Z, Toman M, Faldyna M. Clinical and immunological
characteristics of cats affected by feline infectious peritonitis. Acta
Vet Brno 2000;69(2):51-60.
54.Weiss RC, Cox NR, Boudreaux MK. Toxicologic effects of ribavirin in cats. J Vet Pharmacol Ther 1993;16(3):301-316.
55.Zeidner NS, Myles MH, Mathiason-DuBard CK, et al. Alpha interferon (2b) in combination with zidovudine for the treatment of
presymptomatic feline leukemia virus-induced immunodeficiency
syndrome. Antimicrob Agents Chemother 1990;34(9):1749-1756.
56.Tomkins WA. Immunomodulation and therapeutic effects of the
oral use of interferon α: mechanism of action. J Interferon Cytokine
Res 1999;19(8):817-828.
57.Ishida T, Shibanai A, Tanaka S, et al. Use of recombinant feline
interferon and glucocorticoid in the treatment of feline infectious
peritonitis. J Feline Med Surg 2004;6:107-109.
58.Weiss RC, Cox NR, Oostrom-Ram T. Effect of interferon or
Propionibacterium acnes on the course of experimentally induced
feline infectious peritonitis in specific-pathogen-free and randomsource cats. Am J Vet Res 1990;51(5):726-733.
59.McReynolds C, Macy D. Feline infectious peritonitis. Part II. Treatment and prevention. Compend Contin Educ Pract Vet 1987;19(10):
1111-1116.
60.Addie DD, Jarrett O. Control of feline coronavirus infections
in breeding catteries by serotesting, isolation, and early weaning.
Feline Pract 1995;23(3):92-95.
61.Fehr D, Holznagel E, Bolla S, et al. Placebo-controlled evaluation of a modified live virus vaccine against FIP: safety and efficacy
under field conditions. Vaccine 1997;15(10):1101-1109.
62.Fehr D, Holznagel E, Bolla S, et al. Evaluation of the safety and
efficacy of a modified live FIPV vaccine under field conditions.
Feline Pract 1995;23(3):83-88.
63.Richards JR, Elston TH, Ford RB, et al. The 2006 American Association of Feline Practitioners Feline Vaccine Advisory Panel Report. JAVMA 2006;229(9):1405-1441.
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1. Which is the key inflammatory cell in
the development of FIP?
a. T cell
b. neutrophil
c. macrophage
d. eosinophil
2. Which breed of cat has a genetic susceptibility for the development of FIP?
a. Persian
b. Manx
c. Siamese
d. Ragdoll
3. What percentage of cats exposed to
FECV develop clinical FIP?
a. <10%
b. 20% to 30%
c. 50% to 60%
d. 90% to 100%
4. What finding on brain magnetic resonance imaging is suggestive of FIP?
a. hydrocephalus
b. mass lesion in the cerebral cortex
c. no visible abnormalities
d. cerebral edema
c. They may be falsely negative in cats
with effusive FIP.
d. all of the above
5. What A:G ratio in effusion fluid is suggestive of FIP?
a. <0.5
b. 0.6 to 0.8
c. 0.8 to 1.0
d. >1.0
8. Why are indoor cats more at risk for
developing FIP than outdoor cats?
a. population density
b. environmental stress
c. shared litterboxes
d. all of the above
6. What histologic lesion is not suggestive
of FIP?
a. perivascular inflammation
b. hepatic nodular regeneration
c. tissue necrosis
d. lymphoid depletion
9. What nondomestic feline is most susceptible to FIP?
a. lion
b. tiger
c. cheetah
d. cougar
7. Why should anticoronavirus titers not be
used to definitively diagnose FIP?
a. They cannot distinguish between FIPV
and FECV.
b. Laboratory reporting of titers is
inconsistent.
10. What type of immune response produces dry FIP?
a. strong humoral response
b. strong cell-mediated response
c. partial cell-mediated response
d. INF-γ
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